“It takes 20 years to build a reputation and five minutes to ruin it,” said Warren Buffett, the legendary investor and CEO of Berkshire Hathaway.

The fragility of an organisation’s good name was starkly illustrated this week, as thousands of Google employees in 50 cities around the world staged walkouts in protest at the company’s treatment of women, just days after the search engine group was named the company with the best reputation among millennials by the Reputation Institute.

It was the only company in the ranking to gain an “excellent” score, with the institute saying: “The tech giant displays great consistency with a top 3 ranking among both Millennials and the global public overall, while also coming in poll position in the latest RI CSR ranking.”

Luxury brand Rolex was in second place, with a strong performance on Products, Leadership and Financial Performance while Walt Disney was placed third, scoring highly in Corporate Social Responsibility (CSR) as well as in Leadership, and Performance – dimensions which are all disproportionally important to Millennials.

Stephen Hahn-Griffiths, chief reputation officer at the institute, said: “Rolex’s connection with high-profile sports icons such as Roger Federer has paid dividends and elevated its reputation among a young audience. The embodiment of “success with integrity” makes Rolex an aspirational brand and enables it to forge a strong emotional bond with Millennials. Disney came second only to Google in the ranking for corporate responsibility and has done a superb job communicating their work around green energy and workers pay in a relevant way, with sufficient depth and sincerity.”

The Reputation Institute’s 2018 Millennial RepTrak® report, based on more than 230,000 individual ratings from among the informed general public across the globe, with 145 multi-national companies assessed in January and February 2018.

There are 1.8 billion millennials globally, the institute says, and by 2020, they will comprise 35% of the global workforce, according to Manpower, while Deloitte reports that they will have a net worth of $24 trillion. The top 10 brands are spread fairly evenly across the globe, with three in the US (Google, Walt Disney, Microsoft) and Japan (Nintendo, Sony, Canon) and four from Europe (Rolex, Lego, BMW, Adidas).

The survey suggests that Google’s reputation, among millennials at least, may be safe for now, with products and services the most important single driver of corporate reputation according to the latest figures. They are slightly less concerned about issues of governance and citizenship than non-millennials, but more focused on corporate financial performance.

This group of consumers puts a lot of store in strong corporate leadership, the survey found, with a company’s reputation enhanced if the CEO was familiar to those questioned.

“CEO responsibility is a leading quality for most millennials, highlighting their importance as the face of the company. To improve their reputation among millennials, CEOs need to focus on conveying a sense of social responsibility and ethical behaviour,” Hahn-Griffiths added: “The highest dimension lift among those familiar with CEOs are in the key dimensions of citizenship and governance - Google’s Sundar Pichai is a prime example of a CEO who has got this right and Google are clearly reaping the rewards as a result.